Infrared Thermography for the evaluation of pulsatile or continuous perfusion during cardiopulmonary bypass surgery

Aim of this study was to evaluate the effectiveness of pulsatile perfusion (PP) with respect to continuous perfusion (CP) in CardioPulmonary Bypass (CPB), by InfraRed (IR) thermographic analysis. Twelve elderly patients undergoing aortic valve replacement were divided into two groups treated by either CP or PP pumps. Temperature maps on the sole of the patient's left foot were acquired during surgery by means of an IR thermo-camera. The heating process at the end of the hypothermic surgical phase was analysed in terms of: time delay between the beginning of arterial blood rewarming and foot rewarming; slope of the temperature vs. time tracings and temperature differences among different regions of the foot sole. PP patients showed more prompt answer of the peripheral regions to arterial rewarming (shorter time delay) with respect to CP patients. The slope of the temperature vs. time tracings during the heating phase showed to be steeper in PP than CP. A more homogeneous temperature distribution on the sole of the foot was obtained in PP patients than in CP patients. The IR thermography proved to be a suitable technique to evaluate peripheral perfusion during CPB.